Inductance device and method for operating the same



Jul 15, 1924. 1,501,669

G. A. KELSALL INDUCTANCE DEVICE AND METHO FOR OPERATING THE SAME //7 ken) Geo/78A ffe y MAf/y Patented July 15, 1924.

UNITED STATES waste PATENT OFFICE.

GEORGE A. KELSALL, OF BELLEVILLE, NEW COMPANY. INCORPORATED, OF NEW YOR INDUOTANCE DEVICE AND METHOD FOR OPERATING THE SAME.

Application filed September 9, 1920. Serial No. 409,129.

To all whom it may concern:

Be it known that I, GEORGE A. KnLsALL, a citizen of the United States, residing at Belleville, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Inductance Devices and Methods for Operating the Same, of which the following is a full, clear, concise, and exact description.

This invention relates to inductance devices and more particularly it relates to a unitary loading device for a duplex circuit.

As is well known in the art, it is frequently desirable to, add inductance units to a signaling line in order to improve its transmission characteristics.

An object of this invention is to provide a unitary inductance device which may be inserted in a duplex circuit for simultaneously loading the two physical circuits and the derived phantom circuit whereby the use of an inductance device for each of the three circuits is rendered unnecessary. A

further object is to provide for the three signalingcircuits of a duplex circuit an inductance unit in which the ratio between the physical and phantom loading may be made any desired value.

One form the inductance device of this invention may have, comprises a toroidal core having four radial arms preferably located at angles of 90 with respect to each other. The inductance for each wire of each physical circuit comprises windings on one radial arm and the two adjacent quadrants of the toroid so that each quadrant has a winding included in each side circuit and each radial arm has a winding for one wire of the physical circuits. These windings are so disposed with respect to each other that they substantially neutralize one anothers inductance for current peculiar to the circuit which they are not intended to load, so that cross-talk between the three signaling circuits is either prevented or made unobjectionable. The ratio between the phantom and physical or side circuit loading may be adjusted to any desired value by the proper proportioning of the number of turns on each line winding placed upon the quadrants. 4

This invention will be better understood by reference to the following detailed description taken in connection with the accompanying drawing in which Fig. 1 represents one form of th1s invention embodied in a duplex signaling circuit; Fig. 2 represents the flux produced in the loading unit for current in one side circuit; Fig. 3 represents the flux produced in the core for current in the other side circuit; Fig. 4 represents the flux for the phantom circuit, and Fi 5 illustrates in perspective a form of this invention in which the core is of the so-called cruciform type.

The duplex signaling circuit illustrated in Fig. 1 comprises one side circuit consisting of wires 7, 8, and a second side circuit consisting of wires 9, 10.

Loading unit 27 for the two physical circuits 7, 8, and 9, comprises a cruciform core having the four quadrant portions 19, 20, 21, 22, and the four radial arms 23, 24, and 26. For convenience, and in order to avoid confusion, the line windings for side circuit 7, 8 are shown on a separate core structure from the line windings for the side circuit 9, 10. It is to be understood however, that in actual practice the windings for the two physical circuits would be wound upon the same core structure so that the windings upon the quadrant portions of the core structure for the two physical circuits would be superposed upon each other. Line 7 of the-side circuit 7, 8 is provided with inductance windings 28, 29 and 30, while line 8 is provided with inductance windings 31, 32, and 33. Similarly, line 10 of the physical circuit 9, 10 is provided-with inductance windings 40, 34: and 35, while line 9 is provided with inductance windings 36, 37 and 38. It is to be noted that each line of the side circuit has three windings, one of which is on one ofthe radial arms and the other two of which are located on the two adjacent quadrant portions of the core. It is also to be noted that winding 28 for line 7 is superposed on winding 40 of line 10, winding 30 of line 7 is superposed on winding 36 of line 9, winding 31 of line 8 is superposed on winding 35 of line 10, and winding 33 of line 8 is superposed on winding 38 of line 9. It is to be understood however that if desired, the outer windings may be those of physical circuit 9, 10. It is also notnecessary to have the outer windings on the uadrants composed entirely of windings om a single side circuit.

The flux in the core of loading unit 27 for side circuit 7, 8 is illustrated in Fig. 2 for instantaneous current peculiar to side circuit 7, 8, the direction of the flux being represented b the arrows. The direction of the flux or an instantaneous current flowing serially in side circuit 9, 10, is illustrated by the arrows in Fi 3. It is to be noted from Figs. 2 and 3 tIrat the flux, due to the windings of one side circuit, links with the windings of the other side circuit in such a way that the inductance eflects therein are neutralized, so that the side circuits are therefore non-interfering.

As is evident from Figs-2 and 3, the three windings for each line of each side circuit are aiding, so that the total inductance for line 7, due to windings 28, 29 and 30 is equal to the arithmetical sum of the self inductances or the three windings and the mutual inductances thereof. This arrangement, in which the inductance efiects of the three windings for each line is additive, is advantageous in that the maximum inductance effect is obtained for a given number of turns and the direct currentresistance of the windings is kept to a minimum.

The direction of the flux for the phantom circuit of side circuits 7, 8 and 9, 10 is shown by the direction of the dotted arrows in Fig. 4. Here, for example, the flux leaving the radial arms 23 and 25 divides, flowing in opposite directions through the quadrants 19, 20 and 21, 22 respectively, and there unites and completes its circuit through the radial arms 24, 26. This linkage of the flux through the windings of the two side circuits gives rise to the inductance efiect for the phantom circuit. From the direction of the flux for the side circuits and the phantom circuit, as illustrated in Figs. 2, 3 and 4, it is apparent that the side circuits and the phantom circuit are mutually non-interfering. Attention is also called to the fact that the mutual inductances between windings in different side circuits for phantom circuit currents are all aiding so that maximum phantom loading for windings of a given number of'turns is obtained thereby.

In carrying out this invention in connection with a core of the cruciform ty c, it is referable that the three windings i dreach ine oi each side circuit should be comparable to eachother in regard to the number of turns included in each winding; or, express ing it more broadly, the product of the flux times the magnetic reluctance should be comparable for the three windings of each set. For example, in one case it may be desirable to insert on the radial arm, 30% of the total number of windings for one line, while inserting on each of the two adjacent quadnuances rants, 35% of the total number or windings. In another case it may be desirable to employ 40% on each quadrant and only 20% on the radial arm. In still another case it may be desirable to employ 25% on each quadrant and 50% on the radial arm. This arrangement, in which the total windings foreach line are substantially equally divided between two quadrants and the adjacent radial arm, afiords the most efiicient use of the core structure. Furthermore, by having the three windings comparable to each other it is possible to distribute the windings uniformly over substantially the entire core structure, thereby reducing to a very small Value the amount of magnetic leakage in the loading unit. For example, if 90% of line winding was included on the radial arm, and 5% on each of the adjacent quadrants, it would not be possible in the average case to completely surround the quadrants by the few turns used thereon, so that the amount of magnetic leakage in such a case would generally be of such an amount as to be objectionable. This particularly would be true when the core employed is of material having low permeability such as the iron dust core described and claimed in the U. S. patent to Elmen No. 1,286,965, patented Dec. 10, 1918.

In loading phantom circuits it is frequently desirable to be able to control the ratio of the loading for the phantom with re spect to the loading for the side circuits. In certain cases this ratio may be 0.5 while in other cases it may be as high as 0.6. The above described loading unit aflords a ready means for controlling this ratio of the phantom to the side circuit inductance since the proportion of the phantom circuit loading with respect to the side circuit loading depends, in the form of coil disclosed, primarily upon the number of turns superposed on each of the quadrants. It is evident \from Fig. 1 that when the number of turns on the quadrants are increased, the resultant increase of the number of turns on the quadrants with respect to the number'on radial arms will cause an increase in the ratio of the phantom loading to the side circuit loading. Similarly a decrease in the number of turns on the quadrants will produce a decrease in thematic of the hantom loading to side circuit loading. It ibllows therefore, that the ratio between the phantom and side circuit loading may be given any desired value by the proper proportioning of the number of turns on the quadrants with respect to the number of turns on the radial arms. In no case, however, will it be necessary in this adjustment to make the number of turns of either the quadrants or the radial arms to be so low as to not have them comparable with each other.

The above statements follow from the well known relation, as discussed in the scribed may United States patent to Espenschied, No. 1,233,766, patented 'July 17 1917, that where L'ztotal side circuit inductance; L: total phantom circuit inductance; L: self inductance of each line winding; M: mutual inductance between line windings of the same side circuit; and N mutual inductance between line windings of different side circuits.

F ig. 5 illustrates in perspective the loading unit 27 of this invention as embodied on a cruciform core. As shown in this figure, the windings cover substantially entirely all portions of the core structure,

thereby reducing to a minimum the amount of magnetic leakage therefrom.

It is obvious that the loading unit debe variously modified without departing in any wise from the spirit of this invention as defined in the appended claims.

What is claimed is:

1. The combination with two physical circuits consisting of line conductors, together furnishing a phantom circuit, of an inductance device comprising a magnetic core having a plurality of connected portions, another set of core portions connected to each other and connecting the junctions of the first named portions, and a winding for each line conductor mounted on one of said second named portions and a second winding for each line conductor mounted on and substantially equally divided between two of said first named portions, the number of turns of each Winding for one of said line conductors being substantially of the same order of magnitude.

2. The combination with two physical circuits comprising line conductors, together furnishing a phantom circuit, of an inductance device comprising a magnetic core having a plurality of connected portions, another set of core portions connected to each other and connecting the junctions of the first named portions, anda winding for each of said line conductors on one of said second named portions and the two adjacent first named portions.

3. The combination with two physical circuits comprising line conductors, together furnishing a phantom circuit, of an inductance device comp-rising a magnetic core having a plurality of connected portions, another set. of core portions connected to each other and connecting the junctions of said first named portions, the windings of said core portions for said line conductors, said windings being uniformly distributed over substantiallythe entire body of said core.

4. The combination with two physical circuits, together furnishing a phantom circuit, of an inductance device comprising a magnetic core having a plurality of portions connected to form a closed figure, another Set of core portions connected to each other and connecting the junctions of said first named portions, a winding on each of one set of said portions for each of said two a physical circuits, windings on said other core portions for said physical circuits, said windings being distributed substantially uniformly over the entire core structure whereby magnetic leakage therefrom is substantially prevented.

5. A duplex circuit comprising four conductors and an inductance device comprising a magnetic core having four connected portions, a second set of core portions extending from the junctions of said first named portions, and a winding upon each portion of said two sets of core portions, said windings being distributed substantially uniformly over the entire core-structure whereby magnetic leakage therefrom is substantially prevented, a plurality of said windingsbeing included in each of said conductors.

6. The combination with two physical circuits consisting of line conductors, together furnishing a phantom circuit of a loading coil comprising a core portion of toroidal form, a plurality of other core portions joining opposite sides of said toroid, a winding on each quadrant of said toroid and on each of said other core portions, a plurality of said windings being included in each of said line conductors, the magnetic flux produced by said windings for each line conductor being aiding for currents in the physical circuit to which said conductor belongs, said wind ngs being distributed substantially uni,- formly over the entire core structure whereby magnetic leakage therefrom is substantially prevented.

7. The combination with two physical circuits comprising line conductors, together furnishing a phantom circuit of an inductance device comp-rising a core, portion of toroidal form, radial portions situated 90 from one another and joining opposite sides of said toroid, and windings for said line conductors substantially uniformly distributed over the four quadrants of. said toroid and over said radial portions for preventing appreciable magnetic leakage therefrom.

8. The combination Withtwo physical circuits comprising line conductors, together furnishing aphantom circuit of an inductance device comprising a core portion of toroidal form, radiaL portions situated 90.

from one another and joining opposite sides of said toroid and a winding on each of a plurality of the quadrants of said toroid and on one of said radialportions for each of said line conductors, the magnetic flux produced by said windi s being aiding tor currents in that physidfi circuit to which said. line conductor belongs.

9. The combination of two side circuits comprising line conductors, together furnishing a phantom circuit, an inductance device comprising a core portion of toroidal form, radial portions situated approximately 90 from one another and joining 0 posite sides of said toroid, and a plurality 0 windings on said core for each of said conductors, the inductance of said windings for one of said conductors bein aiding for side circuit currents, the mutua inductance between windings of different side circuits for phantom currents being also aiding, said windings being distributed substantially uniformly over the entire core structure whereby magnetic leakage therefrom is substantially prevented.

10. The combination with two side circuits comprising line conductors, together furnishing a phantom circuit, of an inductance device comprising a magnetic core having a 'plurality of connected portions, another set of core portions connected to each other and connecting the junctions of said first named portions, a winding on each of a plurality of said first portions and on. one of said second named portions for each of said line conductors, the inductance of said windings for one of said conductors bei ending for side circuit currents, the mutua. inductance between windings of diiierent side circuits for phantom currents being also aiding.

11. The combination with two physical circuits comprisin line conductors furnishing a phantom circuit of more than two sets of windings included in each of the conductors of each of said ph sical circuits, the windings belonging to each physical circuit being loosely coupled, a portion of the windmgs belonging to difierent physical circuits being closely coupled, said windings being adapted to produce inductance effects in the physical circuits and also to produce inductance effects in the phantom circuit, and a substantially circumferentially complete magnetic core having substantially its entire surface surrounded b said windings.

12. The combination with two physical circu ts comprising line conductors, together furnishing a phantom circuit of an inductance device compris' a core .portion of toroidal form, and. ra ialportions situated 90 from one another and joinin opposite sides of said toroid, each of sai line 0011- ductors comprisin a winding on one of said. radial ortions an a winding on each of the two a 'acent toroidal quadrants.

13. circuits consisting .of line conductors, to-- ether furnishing the phantom circuit, of an inductance device comprising a ma .etic core having a plurality of connecte por tions, another set of core portions connected to each other and connecting the junctions of the first named portions, and a winding for each line conductor on one of said sec- 0nd named portions and on each of a p1ura1- ity of said first named portions, the inductance for said windings for one of said line conductors being aidlng for physical cir-' cuit currents.

14:. The combination with two physical circuits consisting of line conductors, together furnishing the phantom circuit, of an inductance device comprising a ma etic core having a plurality of connecte portions, another set of core portions connected to each other and connecting the junctions of the first named portions, more than two windings for each line conductor on said core, the inductance of said more than two windings for one line conductor being aiding for physical circuit currents, the mutual inductance between windings in different vphysical circuits being also aiding, said windings being1 uniformly distributed over substantially t e entire core structure.

15. The method of controlling the ratio of phantom to side circuit loading in a duplex circuit which comprises inserting more than two windings in each line of each of the side circuits in such a manner as to aid each other for side circuit currents, producinga close coupling between certain windings 1n difi'erent side circuits, producinga oose coupling between other windings in difierent side circuits, and varyin the number of turns of the loosely coup ed coils with respect to the number of turns of the closely coupled coils:

In witness whereof I hereunto subscribe my name this 7th day of September, A. D..,

GEORGE A. KELSALL.

e combination with two physical 

